When there's an ugly bitch talking to you and you'd just like her to piss off so that you can talk to the more attractive ladies, being the superficial fuck you are. You might try to make up an excuse, but the bitch is more than a little bit aware of how ugly she is and sees through your petty excuses. You end up just running away.

An example of unwanted attention (you're in the bar or some disco looking out for some hot chicks/dudes when someone ugly approaches):
Ugly bitch/dude: "Oh hey want to get a drink?"
You: (Omg look at that ugly bitch holy fuck she's ugly, how the fuck am I going to escape)? "Oh no I'm on quite a heavy period, got to clean up / I've left the cooker running / I've got to take a leak etc.
Ugly bitch/dude: "That's a good excuse! Hey want to get a drink?"
You: *Runs off into the sunset.*